#include <stdio.h>  
#include <stdlib.h>  
#include <string.h>  
#include <sys/types.h>  
#include <sys/stat.h>  
#include <fcntl.h>  

/* usage:  
 * ./bin /dev/hello0 
 */  
void print_usage(char *file)  
{  
    printf("%s <dev>\n", file);  
}  
  
int main(int argc, char **argv)  
{  
    int fd;  
    if (argc != 2)  
    {  
        print_usage(argv[0]);  
        return 0;  
    }  
  
    fd = open(argv[1], O_RDWR);  
    if (fd < 0)  
        printf("can't open %s\n", argv[1]);  
    else  
        printf("can open %s\n", argv[1]);  
  
    return 0;  
}  
